Human Anatomy - M.M. Kurepina, A.P. Ozhigova, A.A. Nikitina 2010

Internal Organs
Urinary System
Urethra

From the Urinary Bladder, urine is discharged externally through the Urethra (urethra) (Atl. Figs. 209, 210).

The male urethra is a tube 18—20 cm long. Its inner surface is lined with a mucous membrane. It is smooth in the upper two-thirds of the canal, and forms longitudinal folds in the lower third. The mucous membrane contains glands whose secretions keep it moist. Three parts are distinguished in the urethra: the prostatic, membranous, and spongy.

The prostatic part begins at the urinary bladder and is surrounded by the Prostate Gland. On the inner surface of the posterior wall of this part of the canal is the seminal colliculus—a small elevation with a slit-like depression. The prostate gland contains A large number of smooth Muscle fibers continuing from the urinary bladder. These fibers form an involuntary internal sphincter around the prostatic part of the canal.

The membranous part is the shortest (0,5—1 cm) and narrowest. It penetrates the Perineum, whose striated Muscles form the external voluntary sphincter of the urethra. With the help of the MUSCLES AND FASCIAE of the perineum, this part of the canal



Last update: 09/08/2026

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